Use of adjuvants to improve abscisic acid performance

ABSTRACT

This invention relates to the use of selected adjuvants to improve the performance of S-(+)-abscisic acid (S-ABA, ABA) or ABA salts on plants.

FIELD OF THE INVENTION

The present invention relates to the use of selected adjuvants ornitrogen containing fertilizer to improve the performance of abscisicacid (ABA) or its salts thereof by increasing the extent and/orextending the duration of desired biological activity.

BACKGROUND OF THE INVENTION

Abscisic acid (ABA) is a natural occurring hormone found in all higherplants (Cutler and Krochko 1999, Trends in Plant Science, 4:472-478;Finkelstein and Rock 2002, The Arabidopsis Book, ASPB, Monona, Md.,1-52). ABA is involved in many major processes during plant growth anddevelopment including dormancy, germination, bud break, flowering, fruitset, general growth and development, stress tolerance, ripening,maturation, organ abscission, and senescence. ABA also plays animportant role in plant tolerance to environmental stresses, such asdrought, cold, and excessive salinity.

One key role of ABA in regulating physiological responses of plants isto act as a signal of reduced water availability to reduce water loss,inhibit growth and induce adaptive responses. All these functions arerelated to stomatal closure (Raschke and Hedrich 1985, Planta, 163:105-118). When stomata close, plants conserve water to surviveenvironmental stresses. However, stomatal closure also can result inreduced photosynthesis, respiration and growth. Stomatal closure is arapid response of plants to ABA. The mechanism of this effect has beenstudied and has been shown to be due primarily to ABA effects on guardcell ion channels. Specifically, ABA blocks H⁺ extrusion and K⁺ influxfrom guard cells and promotes K⁺, Cl⁻, and malate extrusion and Ca²⁺influx. The net effect of ABA is to reduce the total osmotica in theguard cells, which in turn decreases the water content in the cell. Thiscauses the guard cells to lose turgor and thus close the stomata(Assmann 2004, In: Plant Hormones Biosynthesis, Signal Transduction,Action, ed. Davies, p 391-412). The closing of the stomata results inreduced transpiration. The reduction of transpiration caused by stomatalclosure is widely used as an experimental technique to indirectlyidentify and quantify ABA activity. The ability of ABA to reduce wateruse can not only extend the display shelf life of ornamentals or thepostharvest shelf life of leafy plants, or promote drought tolerance,but it also can lead to a reduction in cold stress injury (Aroca et al.2003, Plant Sci., 165: 671-679). ABA-induced reduction of stomatalconductance can lead to a decrease in photosynthesis (Downton et al.1988 New Phytol., 108: 263-266) which in turn can lead to growthcontrol. Improving the performance of ABA may be useful not only forimproving the reduction of transpiration and water loss, but also forother uses of foliar applied ABA such as maintaining dormancy of budsand seeds, controlling fruit set, accelerating defoliation, andenhancing color development of fruit such as grapes.

Surfactants or adjuvants have long been used with pesticides and plantgrowth regulators to increase the absorption or uptake by plants andthus improve the performance of the applied chemicals. Adjuvants includewetter-spreaders, stickers, penetrants, compatibility agents andfertilizers. However, there is little prior art information aboutadjuvant effects on ABA efficacy. In the patent application ofQuaghebeur (2005, US20050198896 Al) it is noted that “ethoxylatedsorbitan esters and siloxanes have proved to be particularly suitablefor the application of ABA”, but there is no mention of adjuvant effectson ABA efficacy. Lee et al. (1997, Kor. Soc. Hort. Sci. J., 38:717-721)reported that the addition of 0.05% Tween 20 (a commercially availableethoxylated sorbitan ester) improved ABA effect. However, Tween 20 isused for academic research and not packaged and distributed for theagricultural market.

The pH of an exogenously applied ABA solution may play a role indetermining the efficiency of ABA uptake by plants. At an acidic pH, ABAis in its neutral undissociated form. This form is more lipophilic, andits penetration of the plant cuticle would be favored relative to thecharged, dissociated form of ABA present at higher pHs (Blumenfeld andBukovac 1972, Planta, 107:261-268). The uncharged undissociated form ofABA would more easily cross cell membranes from the relatively acidicapoplast into the cytosol.

Foliar applied nitrogen fertilizers, such as urea or ammonium nitrate,have been used in combination with plant growth regulators (PGRs) toimprove the performance of the PGR. For example, the combination of thePGRs benzyladenine (Naito et al. 1974, J. Japan. Soc. Hort. Sci., 43:215-223) or gibberellic acid (Shulman et al. 1987, Plant Growth Regul.,5: 229-234) with urea increased the grape berry sizing effect comparedto the sizing effect achieved with the PGR alone. Ammonium salts havebeen reported to increase the absorption of pesticides (Wang and Liu2007, Pestic. Biochem., Physiol., 87: 1-8). Nooden (1986, U.S. Pat. No.4,581,057) claims the use of ABA to increase fertilizer performance.However, there are no reports of the use of urea (H₂NCONH₂) or ammoniumnitrate (NH₄NO₃) to improve ABA performance.

In order maximize the performance of ABA in its various agricultural andhorticultural applications; there is a need to improve the extent andduration of ABA efficacy.

SUMMARY OF THE INVENTION

The present invention is directed toward the incorporation of aneffective amount of an adjuvant selected from the group consisting ofpolyoxyethylene fatty alcohol ethers, nonylphenyl ethoxylates andphthalic/glycol alkyl resins into an ABA or ABA salt-containing end-usesolution composition or into a liquid or solid formulation compositionintended for preparation of such an end-use solution in order toincrease the effectiveness of ABA by increasing the extent and/orextending the duration of its desired biological activity. This is thenaccomplished by applying said end-use solution composition directly totarget plants or the locus thereof by spraying or drenching.

The present invention is also directed to the incorporation of aneffective amount of an adjuvant selected from the group consisting ofpolyoxyethylene fatty alcohol ethers, nonylphenyl ethoxylates andphthalic/glycol alkyl resins into an ABA or ABA salt-containing end-usesolution composition in order to decrease the ABA application raterequired to attain a targeted degree or duration of ABA biologicalactivity.

The present invention is also directed to the incorporation of aneffective amount of an adjuvant selected from the group consisting ofpolyoxyethylene fatty alcohol ethers, nonylphenyl ethoxylates andphthalic/glycol alkyl resins into an ABA or ABA salt-containing inbottle formulation in order to decrease the ABA application raterequired to attain a targeted degree or duration of ABA biologicalactivity.

The presently preferred polyoxyethylene fatty alcohol ethers useful inthe present invention are members of the Brij family of surfactants. Themost preferred member of the Brij family of surfactants is Brij 98(polyoxyethylene (20) oleyl ether).

A presently preferred nonylphenol ethoxylate is Agral 90.

A presently preferred phthalic/glycol alkyl resin is Latron B1956.

The present invention is also directed to the incorporation of aneffective amount of Brij 98 (polyoxyethylene (20) oleyl ether) and anitrogen containing fertilizer, such as urea into an ABA-containingend-use solution or formulation that is diluted to produce an end-usesolution, and to the application of said solution to a plant or plantsor to the locus of a plant or plants.

DETAILED DESCRIPTION OF THE INVENTION

The compositions of the present invention improve ABA effectiveness byincorporating a surfactant, and optionally a nitrogen-containingfertilizer together with an effective amount of the plant growthregulator abscisic acid (S-ABA; ABA; S-(+)-abscisic acid; +-ABA,(+)-(S)-cis,trans-abscisic acid, (+)-(S)-cis,trans-ABA; S-ABA;(S)-5-(1-hydroxy-2,6,6,-trimethyl-4-oxo-2-cyclohexen-1-yl)-3-methyl-(2Z,4)-pentadienoicacid; CAS registry no. [21293-29-8]). ABA effectiveness may be measuredexperimentally by quantifying the inhibition of transpiration in tomatoleaves. This is a reliable laboratory bioassay of the level of ABAactivity.

The compositions of the present invention comprise ABA or a saltthereof, together with a polyoxyethylene fatty alcohol ether,nonylphenol ethoxylate or phthalic/glycol alkyl resin adjuvant, and maybe used to form to a ready-to-apply liquid solution, a mixture preparedby the end user of the ABA or a solid or liquid formulation concentrate.The effectiveness of the compositions of the present invention wasdemonstrated by tomato leaf transpiration inhibition. The response oftomato plants to ABA is representative of the response of other plantspecies, such as nursery plants, to ABA. Other physiological processesregulated by ABA such as the promotion of drought tolerance of beddingplants, fruit coloration, dormancy of buds and seeds, plant growthcontrol, defoliation, and chilling and freeze stress protection areexpected to respond to the combinations of ABA or ABA salts withadjuvants of this invention.

The presently preferred surfactants for incorporation into the ABAcompositions of the present invention are members of the Brij family(polyoxyethylene fatty alcohol ethers), available from Uniqema (Castle,Del.), including Brij 58 (polyoxyethylene (20) cetyl ether), Brij 76(polyoxyethylene (10) stearyl ether), Brij 78 (polyoxyethylene (20)stearyl ether), Brij 98 (polyoxyethylene (20) oleyl ether) and Brij 700(polyoxyethylene(100) stearyl ether); Agral 90 (Nonylphenol ethoxylate)available from Norac Concept. Inc. (Orleans, Ontario, Canada) and LatronB-1956 (77.0% modified phthalic/glycerol alkyl resin and 23.0% Butylalcohol) available from Rohm & Haas (Philadelphia, Pa.). The presentlymost preferred surfactant for incorporation into the ABA compositions ofthe present invention is Brij 98 (polyoxyethylene (20) oleyl ether),optionally in combination with nitrogen-containing fertilizers or otheradjuvants.

The presently preferred combination of nonionic surfactant and anionicwetting agent for improving ABA performance is Brij 98 plus MonawetMO-84R2W (84% sodium dioctyl sulfosuccinate anionic wetting agent inpropylene glycol solvent) in a suitable solvent such as ethyl lactate.

The presently preferred combination of surfactant andnitrogen-containing fertilizer for improving ABA performance is Brij 98and urea.

As used herein, the term “salt” refers to the water soluble salts of ABAor ABA analogs or derivatives, as appropriate. Representative such saltsinclude inorganic salts such as the ammonium, lithium, sodium,potassium, calcium and magnesium salts and organic amine salts such asthe triethanolamine, dimethylethanolamine and ethanolamine salts.

Depending on the target plant species, physiological processes ofinterest, and environmental conditions, the effective concentration ofABA can vary, but it is generally in the range of about 0.1 ppm to about10,000 ppm, and preferably from about 1 to about 1000 ppm.

The preferred concentration of nonionic surfactant or/and anionicwetting agent surfactant in the end-use solutions of the presentinvention is about 0.001% to about 25% w/v, preferably from about 0.01%to about 5.0%.

Thus, a presently preferred composition of the present inventioncomprises from about 0.1 ppm to about 10,000 ppm ABA, from about 0.05 toabout 5.0% weight of a surfactant or/and wetting agent, optionally fromabout 0.1 mM to about 1000 mM of a nitrogen-containing fertilizer, withthe balance of the composition consisting of water.

The effective concentration range of ABA depends on the water volumeapplied to plants as well as other factors such the plant age and size,the plant species and varietal sensitivity to ABA, and the targetedphysiological process.

The invention is illustrated by, but is not limited by, the followingrepresentative examples.

EXAMPLES

Preparation of plant specimens for use in the treatment studies of theexamples described was carried out as follows. Tomato (variety: Rutgers)seeds were sown in an 18-cell flat filled with Promix PGX (availablefrom Premier Horticulture Inc. Quakertown, Pa.) and grown for 3 weeks toallow for germination and initial growth. Plants were then transplantedinto pots (18 cm in diameter and 18 cm in height), filled with Promix BX(available from Premier Horticulture Inc. Quakertown, Pa.), and grownfor one or two more weeks before treatment, depending on temperature andavailable light. Plants received daily irrigation and weekly fertilizer(1 g/L all purpose fertilizer 20-20-20, available from The ScottsCompany, Marysville, Ohio).

All treatment solutions were prepared with distilled water. ABA (95%active ingredient) is available from Lomon BioTechnology Co., Ltd.(Shichuan, China). Twenty L of 250 ppm ABA solution was prepared andstored in the dark at 20-25° C. This 250-ppm ABA solution was used forall studies to eliminate the possibility of applying an incorrectconcentration of ABA.

Brij 98, Monawet MO-84R2W, Tween 20 and Tween 60 are available fromUniqema (New Castle, Del.). Ethyl lactate used to solubilize Brij 98 isavailable from Fluka Chemie GmbH (Buchs, Germany). Silwet L-77 isavailable from GE Silcones (Wilton, Conn.).

Agral 90 is available from Norac Concept. Inc. (Orleans, Ontario,Canada).

Latron B-1956 is available from Rohm & Haas (Philadelphia, Pa.).

Unless otherwise specified, when a surfactant was employed, it wasincorporated into the 250-ppm ABA treatment solution at a concentrationof 0.05% to 0.5% (v/v).

ABA solutions and blank treatments were applied to the aerial parts oftomato plant leaves at the rate of 20 mL per 6 plants. Plants were thenplaced in a transparent chamber with humidity controlled within therange of 40 to 60% relative humidity. Leaf transpiration rates weremeasured at 1, 2 and 3 days; at 1, 2, 3 and 4 days; or at 1, 2, 3, 4 and7 days after treatment. Measurements were conducted using a LI-1600Steady State Porometer (LI-Cor, Lincoln, Neb.). Each day thetranspiration rate of the plants of each treatment group was normalizedto the percentage of the transpiration rate of untreated plants (plantssprayed with water only) in order to control for day-to-day variabilitycaused by changes of environmental conditions such as light intensityand temperature. In some cases, data of each plant was averaged over a3-day period to balance the short term and long-term effect of ABA ontomato leaf transpiration as well as to control for experimentalvariability.

A grape coloring field study was conducted at Caruthers, Calif. ABAalone at 100 or 200 ppm or its combination with 0.05% Brij 98 was foliarapplied to Crimson seedless grapes. Number of clusters with color wascounted on a weekly basis, beginning at 21 days after treatment.Percentage of clusters with color was calculated. Grape yield washarvested at 64 days after treatment.

A grape coloring field study was conducted at Caruthers, Calif. ABAalone at 100 or 200 ppm or its combination with 0.05% Latron B-1956 wasfoliar applied to Crimson seedless grapes. Number of clusters with colorwas counted on a weekly basis, beginning at 21 days after treatment.Percentage of clusters with color was calculated. Grape yield washarvested at 64 days after treatment.

All experiments were conducted using a randomized complete blockexperimental design. Data were analyzed by analysis of variance.Duncan's new multiple range tests at α=0.05 were used for meanseparations.

Example 1

Tomato plants treated with various concentrations of ABA alone or incombination with 0.05% Brij 98 were studied (Table 1). ABA alonesignificantly reduced tomato leaf transpiration when applied at 250, 500and 1000 ppm, but not at 125 ppm over the 3-day period. Transpirationinhibition increased with increasing ABA concentrations. Transpirationinhibition from the ABA application was greater when the ABA was appliedwith 0.05% Brij 98 compared to the same ABA concentration appliedwithout adjuvant.

The relationship between relative transpiration and the base-10logarithm of ABA concentration was linear with or without 0.05% Brij 98(Table 1). ABA concentrations for 50% inhibition of transpiration werecalculated to be 3328 ppm without Brij 98 and 191 ppm with 0.05% Brij98. These results demonstrate that the addition of Brij 98 surfactantincreases ABA performance as measured by the tomato leaf transpirationinhibition bioassay.

TABLE 1 The relationship between applied ABA concentration and tomatoleaf transpiration with or without 0.05% Brij 98 Transpiration rate (%of control) ABA Concentration without (ppm) Log₁₀[ABA] 0.05% Brij 98with 0.05% Brij 98 0 100 103 125 2.1 96 58 250 2.4 88 45 500 2.7 74 321000 3.0 68 25 Equation* y = 164 − 32 x y = 134 − 37 x R² 0.98 0.98 ABAconcentrations to achieve 3328 ppm 191 ppm 50% inhibition oftranspiration *In this equation, y is the relative transpiration (% ofcontrol) of the average value of first 3 days after treatment; x is thebase 10 logarithm of ABA concentration.

Example 2

The effect of varying Brij 98 concentrations on the efficacy of 250-ppmABA treatment was examined (Table 2). The addition of Brij 98significantly improved ABA performance. The transpiration rate decreasedwith the increasing concentrations of Brij 98. Transpiration inhibitionlasted longer at higher concentrations of Brij compared to that achievedwith lower concentrations Brij 98. Results demonstrate that a higherconcentration of Brij 98 applied with ABA improves ABA performance ascompared to a lower concentration of Brij 98.

TABLE 2 Effect of varying the concentration of Brij 98 on ABAperformance as measured in the tomato leaf transpiration inhibitionbioassay. Transpiration rate (% of control) Days after treatmentTreatment 1 2 3 Control 100 100 100 250 ppm ABA 76 99 93 250 ppm ABA +0.01% Brij 98 54 97 99 250 ppm ABA + 0.05% Brij 98 25 56 67 250 ppmABA + 0.10% Brij 98 16 41 49 250 ppm ABA + 0.50% Brij 98 7 32 46

Example 3

The effect of 0.05% Tween 60 to improve ABA performance was examined andcompared to the effect of 0.05% Brij 98 to improve ABA performance(Table 3). Both 0.05% Tween 60 and 0.05% Brij 98 significantly improvedABA performance as measured by the tomato leaf transpiration inhibitionbioassay. However, the transpiration rates of plants treated with ABAalone and plants treated with ABA plus Tween 60 were much higher thanthe transpiration rates of plants treated with ABA plus Brij 98. Theseresults demonstrate that Brij 98 is much more effective than Tween 60 inimproving ABA performance for leaf transpiration inhibition.

TABLE 3 Comparison between Brij 98 and Tween 60 for improving ABAinhibition of tomato leaf transpiration. Treatment Transpiration rate (%of control) Control 100 250 ppm ABA 83 250 ppm ABA + 0.05% Brij 98 32250 ppm ABA + 0.05% Tween 60 69 Data listed in the table was the averagevalue of first 3 days after treatment.

Example 4

The effect of 0.05% Silwet L-77 to improve ABA performance was examinedand compared to the effect of 0.05% Brij 98 to improve ABA performance(Table 4). Both 0.05% Silwet L-77 and 0.05% Brij 98 significantlyimproved ABA performance as measured by the tomato leaf transpirationinhibition bioassay. However, the transpiration rates of plants treatedwith either ABA alone or with ABA plus Silwet L-77 were much higher thanthose of plants treated with ABA plus Brij 98. Results indicate thatBrij 98 is much more effective in improving ABA performance than SilwetL-77.

TABLE 4 Comparison between Brij 98 and Silwet L-77 to improve ABAinhibition as measured by the tomato leaf transpiration inhibitionbioassay. Treatment Transpiration rate (% of control) Control 100.02 250ppm ABA 96.32 250 ppm ABA + 0.05% Brij 98 41.23 250 ppm ABA + 0.05%Silwet L-77 64.25 Data listed in the table was the average value offirst 3 days after treatment.

Example 5

Three Brij family surfactants with the same polyoxyethylene oligomerlength, Brij 58, Brij 78, and Brij 98 were tested for their effect onABA performance as measured by the tomato leaf transpiration inhibitionbioassay (Table 5). Each of the three surfactants was tested at 0.05%and 0.5% concentrations. Brij 58, Brij 78 and Brij 98 at eitherconcentration significantly improved ABA performance. For eachsurfactant, ABA applied with the higher surfactant concentration wasmore effective than ABA applied with the lower surfactant concentration.Of the three surfactants, Brij 98 improved ABA performance best.

TABLE 5 Comparison of surfactants in Brij family having the samepolyoxyethylene tail length for improvement of ABA performance asmeasured by inhibition of tomato leaf transpiration Transpiration rate(% of control) Days after treatment Treatment 1 2 3 4 Control 100 100100 100 250 ppm ABA 82 91 90 100 250 ppm ABA + 0.05% Brij 58 44 47 60 99250 ppm ABA + 0.50% Brij 58 29 44 45 70 250 ppm ABA + 0.05% Brij 78 3944 53 97 250 ppm ABA + 0.50% Brij 78 22 42 46 75 250 ppm ABA + 0.05%Brij 98 36 41 52 74 250 ppm ABA + 0.50% Brij 98 24 28 41 51

Example 6

Brij 76 was examined and compared to Brij 98 for its effect on ABAperformance as measured by inhibition of tomato leaf transpiration(Table 6). Inclusion of Brij 76 at 0.05% or 0.5% significantly improvedABA performance. ABA applied with 0.5% Brij reduced transpiration morethan ABA applied with 0.05% Brij 76 did. At the same ABA concentration,ABA applied in conjunction with Brij 98 was more effective than ABAapplied with Brij 76.

TABLE 6 Comparison of two Brij surfactants for improvement of ABAperformance as measured by inhibition of tomato leaf transpiration.Transpiration rate (% of control) Days after treatment Treatment 1 2 3 4Control 100 100 100 100 250 ppm ABA 71 84 86 90 250 ppm ABA+0.05% Brij98 27 43 53 64 250 ppm ABA+0.05% Brij 76 33 43 66 72 250 ppm ABA+0.50%Brij 76 29 29 45 54

Example 7 Preparation of an Aqueous Solution Composition of the AmmoniumSalt of (S)-(+)-abscisic Acid Comprising Potassium Sorbate

In a 600 mL beaker, 55 g of (S)-(+)-abscisic acid of 95% purity wasadded, followed by 500 μL of Tween 20 and 200 mL of water. Then, 10 mLof concentrated aqueous ammonia was added with stirring until themixture came to equilibrium. Then, additional concentrated ammonia wasadded dropwise until all the solid was dissolved. A homogenous solutionwas achieved when a total of about 13.5 mL of ammonia has been added. Atthis point, potassium sorbate (1.25 g) was added to the composition; itquickly dissolved. The mixture was transferred to a 500 ml volumetricflask and was brought up to 500 mL total volume with deionized water.The mixture was stored in a brown glass bottle. The pH was measured tobe 6.50.

An aqueous solution composition comprising 10% abscisic acid as theammonium salt by weight, and further comprising a naturally-occurringantimicrobial preservative, was prepared.

Example 8 Preparation an Aqueous Solution Composition of the AmmoniumSalt of (S)-(+)-abscisic Acid Comprising Brij 98 Surfactant

A solution was prepared containing 5.0 g of Brij 98 in approximately 20mL of water. (S)-(+)-abscisic acid (2.64 g of 95% purity) was added,followed by the theoretical amount of ammonia as the commercialconcentrated aqueous solution. All of the abscisic acid quicklydissolved. Preservative (63 mg of potassium sorbate) was added, and itquickly dissolved. The pH of the resulting clear solution was 6.92. Itwas made up to a final volume of 50 mL to give a concentration of 5%abscisic acid as the ammonium salt and 10% Brij 98 by weight.

An aqueous solution composition comprising 5% abscisic acid by weight asthe ammonium salt and further comprising a high concentration of Brij 98surfactant was prepared.

Example 9

The difference between ABA and ABA ammonium salt was compared with orwithout 0.05% Brij 98 (Table 7). Both ABA and its ammonium salt at 250ppm concentration decreased the transpiration rate. The addition of0.05% Brij 98 into ABA or its ammonium salt significantly improved theirperformance. The transpiration rate was higher for ABA with or withoutBrij 98 than ABA ammonium salt with or without Brij 98.

TABLE 7 Effect of Brij 98 on improving performance of ABA or ABAammonium salt for tomato leaf transpiration inhibition. Transpirationrate (% of control) Days after treatment Treatment 1 2 3 Average Control100 100 100 100 250 ppm ABA 73 76 94 81 250 ppm ABA + 0.05% Brij 98 2539 42 35 250 ppm ABA ammonium salt 68 73 84 75 250 ppm ABA ammoniumsalt + Brij 17 19 32 23 98

Example 10 Preparation of an Aqueous Solution Composition of theTriethanolamine Salt of (S)-(+)-abscisic Acid Comprising a HighConcentration of Brij 98 Surfactant

To a solution of 50 mg Tween 20 in 10 mL of water was added 2.64 g of(S)-(+)-abscisic acid (10 mmoles of 95% purity). Triethanolamine (1.33mL, 10 mmoles) was added dropwise with good stirring, resulting in aclear, homogeneous solution. This solution was heated to 55° C., andBrij 98, liquified by warming in a 55° C. oven, was added. Afterstirring to achieve a homogeneous solution, the mixture was diluted withadditional water to a final volume of 25 mL.

An aqueous solution composition comprising 10% abscisic acid by weightas the triethanolamine salt and further comprising 20% by weight Brij 98as a performance enhancing additive was prepared.

Example 11

The effect of ABA triethanolamine salt with Brij 98 on tomato leaftranspiration was studied (Table 8). ABA triethanolamine salt at a rateequivalent to 250 ppm ABA applied together with Brij 98 significantlyimproved ABA performance. The result demonstrates that Brij 98incorporated into a treatment can improve ABA salt performance fortranspiration inhibition.

TABLE 8 Effect of ABA triethanolamine salt with Brij 98 on tomato leaftranspiration. Transpiration rate (% of control) Days after treatmentTreatment 1 2 3 Average Control 100 100 100 100 250 ppm ABA 71 75 88 78250 ppm ABA triethanolamine salt + 29 28 39 32 Brij 98

Example 12

Brij 98 at 0.05% and the combination of 0.05% Brij 98 with 10 or 100 mMurea were examined for improvement of ABA performance (Table 9). ABAapplied with Brij 98 and ABA applied with Brij 98 in combination with 10or 100 mM urea significantly improved ABA performance as measured bytomato leaf transpiration inhibition over a 3-day period. The additionof urea to Brij 98 plus ABA solution provided more transpirationinhibition than ABA applied in conjunction with Brij 98. Inclusion of ahigh concentration of urea showed a similar effect as the lowconcentration of urea. Results demonstrate that Brij 98 and urea havepositive effects on ABA performance.

TABLE 9 Effect of Brij 98 or Brij 98 plus urea on ABA performance asmeasured by tomato leaf transpiration inhibition. Transpiration rate (%Treatment of control) Control 100 250 ppm ABA 73 250 ppm ABA + 0.05%Brij 98 34 250 ppm ABA + 10 mM Urea + 0.05% Brij 98 28 250 ppm ABA + 100mM Urea + 0.05% Brij 98 27 Data listed in the table was the averagevalue of first 3 days after treatment.

Example 13 Preparation of an Aqueous Solution Composition of theAmmonium Salt of (S)-(+)-abscisic Acid Comprising Brij 98 Surfactant andUrea

A solution of Brij 98 (5.0 g) was prepared in 10 mL warm water. Adding2.64 g of (S)-(+)-abscisic acid (10 mmoles of 95% purity) and stirringproduced a milky suspension. Adding the theoretical amount ofconcentrated aqueous ammonia caused the abscisic acid to dissolvequickly. Urea (6.01 g, 100 mmoles) dissolved quickly when added. Thesolution was made up to a final volume of 25 mL by addition of deionizedwater.

An aqueous solution composition comprising 10% abscisic acid by weightas the ammonium salt and further comprising both 20% by weight Brij 98and 24% urea as performance enhancing additives was prepared.

Example 14 Preparation of an Aqueous Solution Composition of theAmmonium Salt of (S)-(+)-abscisic Acid Comprising Brij 700 Surfactant

Brij 700 (5.0 g) was dissolved in 25 mL of water with the aid of heatand stirring. (S)-(+)-abscisic acid (2.64 g of 95% purity) was added,followed by the theoretical amount of ammonia as the commercialconcentrated aqueous solution. All of the abscisic acid quicklydissolved. Antimicrobial preservative (63 mg of potassium sorbate) wasadded, and it quickly dissolved. The resulting solution was made up to50 mL by addition of deionized water.

An aqueous solution composition comprising 5% abscisic acid by weight asthe ammonium salt and further comprising a high concentration of Brij700 surfactant was prepared.

Example 15

The effect of ABA ammonium salt+Brij 98+Urea and ABA ammonium salt+Brij700 at rates equivalent to 250 ppm ABA on tomato transpiration wasstudied (Table 10). The combination of ABA ammonium salt+Brij 98+Ureadecreased transpiration much more effectively than ABA alone or ABAammonium salt only. The combination of ABA ammonium salt+Brij 98+Ureaalso decreased transpiration more effectively than 250 ppm ABA with0.05% Brij 98 except on the first day after treatment. The combinationof ABA ammonium salt+Brij 700 decreased transpiration more than ABA orABA ammonium salt alone. However, the combination of ABA ammoniumsalt+Brij 700 decreased transpiration less than ABA plus 0.05% Brij 98.These results demonstrate that the incorporation of Brij or thecombination of Brij 98 with urea in a treatment with ABA salt improvedABA performance for transpiration inhibition.

TABLE 10 Effect of Brij alone or its combination with urea on improvingABA ammonium salt performance for tomato leaf transpiration inhibitionTranspiration rate (% of control) Days after treatment Treatment 1 2 3Average Control 100 100 100 100 250 ppm ABA 59 71 77 69 250 ppm ABA +0.05% Brij 98 10 29 38 25 250 ppm ABA ammonium salt 58 67 78 68 250 ppmABA ammonium salt + 15 28 28 24 Brij 98 + Urea 250 ppm ABA ammoniumsalt + 19 37 47 34 Brij 700

Example 16

The combination of two adjuvants, 0.04% Brij 98 with 0.01% MonawetMO-84R2W, was compared to 0.05% Brij 98 on improving ABA performance fortranspiration inhibition (Table 11). The addition of 0.05% Brij 98 or0.04% Brij 98 with 0.01% Monawet MO-84R2W into 250 ppm ABA significantlydecreased the transpiration rate more than 250 ppm ABA alone. However,there was no significant difference between 0.05% Brij 98 and 0.04% Brij98 with 0.01% Monawet MO-84R2W on improving ABA performance fortranspiration inhibition over a 3-day period. These results demonstratethat the combination of Brij 98 with another type of adjuvant such aswetting agent Monawet MO-84R2W had similar effects to those produced byBrij 98 at 40-60% relative humidity. This combination may have advantageover Brij 98 alone at low humidity conditions.

TABLE 11 Effect of Brij 98 alone or its combination with MonawetMO-84R2W on improving ABA performance for tomato transpirationinhibition. Transpiration rate (% of control) Days after treatmentTreatment 1 2 3 Average Control 100 100 100 100 250 ppm ABA 83 85 94 87250 ppm ABA + 0.05% Brij 98 25 33 47 35 250 ppm ABA + 0.04% Brij 98 + 3441 40 38 0.01% Monawet MO-84R2W

Example 17

The effect of 0.05% Brij 98 on ABA (100 or 200 ppm) performance in grapecoloration was examined in the field (Table 12). Addition of Brij 98increased the percent of clusters with color for ABA at 100 or 200 ppmafter application and increased the harvest yield percent withsufficient color. Treatment with 200 ppm ABA had more colored clustersand yield.

TABLE 12 Effect of Brij 98 on improving ABA performance in CrimsonSeedless grape coloration. Days after application (% clusters withcolor) Harvest Treatment 21 27 35 43 50 56 62 64 yield (%) Untreatedcontrol 0.2 0.6 1.9 4.5 4.5 10.5 10.5 14.3 8.1 ABA (100 ppm) 1.8 2.7 5.77.5 9.4 26.1 26.2 31.2 25.5 ABA (200 ppm) 7.0 10.7 17.3 20.5 22.7 47.950.3 56.4 49.1 Brij 98 (0.05%) + 2.0 5.0 9.6 14.6 18.2 31.6 36.8 39.330.3 100 ppm ABA Brij 98 (0.05%) + 14.6 16.4 23.7 30.1 34.5 58.4 60.671.7 61.4 200 ppm ABA

Example 18

The efficacy of 0.05% or 0.5% Agral 90 for improvement of ABAperformance was examined (Table 13). Agral 90 at either 0.05% or 0.5%concentration significantly improved ABA performance as measured bytranspiration inhibition. Agral 90 at 0.5% with 250 ppm ABA caused lowertranspiration rate than 0.05% Agral 90 with 250 ppm ABA. These resultsdemonstrate that the commercially available surfactant Agral 90 can beused as an effective surfactant to improve ABA performance.

TABLE 13 Effect of Agral 90 to improve ABA performance as measured byinhibition of transpiration in tomato leaf Transpiration rate (% ofcontrol) Days after treatment Treatment 1 2 3 4 Control 100 100 100 100250 ppm ABA 74 82 95 100 250 ppm ABA + 0.05% Agral 90 36 45 57 75 250ppm ABA + 0.50% Agral 90 9 38 36 51

Example 19

The efficacy of 0.05% or 0.5% Latron B-1956 for improvement of ABAperformance was examined (Table 14). Latron B-1956 at either 0.05% or0.5% concentration significantly improved ABA performance as measured bytranspiration inhibition. Latron B-1956 at 0.5% with 250 ppm ABA reducedthe transpiration rate more effectively than 0.05% Latron B-1956 with250 ppm ABA. These results demonstrate that the commercially availablesurfactant Latron B-1956 can be used to improve ABA performance.

TABLE 14 Effect of Latron B-1956 to improve ABA performance as measuredby inhibition of tomato leaf transpiration Transpiration rate (% ofcontrol) Days after treatment Treatment 1 2 3 4 Control 100 100 100 100250 ppm ABA 74 82 95 100 250 ppm ABA + 0.05% Latron B-1956 49 53 59 72250 ppm ABA + 0.50% Latron B-1956 41 47 46 63

Example 20

The effect of 0.05% Latron B-1956 on ABA (100 or 200 ppm) performance ingrape coloration was examined (Table 15). Addition of Latron B-1956increased the percent clusters with color for ABA at 100 or 200 ppmafter application and increased the harvest yield percent withsufficient color. ABA at 200 ppm with or without Latron B-1956 had morecolor and greater yield than at 100 ppm.

TABLE 15 Effect of Latron B-1956 on improving ABA performance in CrimsonSeedless grape coloration. Days after application (% clusters withcolor) Harvest Treatment 21 27 35 43 50 56 62 64 yield (%) Untreatedcontrol 0.2 0.6 1.9 4.5 4.5 10.5 10.5 14.3 8.1 ABA (100 ppm) 1.8 2.7 5.77.5 9.4 26.1 26.2 31.2 25.5 ABA (200 ppm) 7.0 10.7 17.3 20.5 22.7 47.950.3 56.4 49.1 Latron B-1956 (0.05%) + 4.6 5.5 15.1 18.5 21.6 48.1 48.954.5 47.9 100 ppm ABA Latron B-1956 (0.05%) + 8.8 11.9 21.3 25.5 29.454.5 55.2 64.2 54.0 200 ppm ABA

1. An agricultural composition comprising an agriculturally effectiveamount of ABA or its salts and a surfactant.
 2. The composition of claim1 that further comprises a fertilizer.
 3. The composition of claim 1wherein the surfactant is of the polyoxyethylene fatty alcohol ethersurfactant family.
 4. The composition of claim 3 wherein the surfactantis Brij
 98. 5. The composition of claim 1 wherein the surfactant is ofthe nonylphenol ethoxylate family.
 6. The composition of claim 5 whereinthe surfactant is Agral
 90. 7. The composition of claim 1 wherein thesurfactant is of the phthalic/glycol alkyl resin family.
 8. Thecomposition of claim 7 wherein the surfactant is Latron B1956 or MonawetMO-84R2W.
 9. The composition of claim 2 wherein the fertilizer is anitrogen-containing fertilizer selected from the group consisting ofurea, ammonium nitrate and ammonium sulfate.
 10. The composition inclaim 9 wherein the fertilizer is urea.
 11. A method for enhancing andextending the effect of ABA or its salts on plants by applying thecomposition of claim 1 to plants.
 12. A method for enhancing andextending the effect of ABA or its salts on plants by applying thecomposition of claim 2 to plants.
 13. The method of claim 11 wherein thesurfactant is selected from the group consisting of Brij 98, Agral 90and Latron B1956.
 14. The method of claim 12 wherein the fertilizer isurea.